Heat dissipation unit and heat dissipation device using same

ABSTRACT

A heat dissipation unit and a heat dissipation device using same are disclosed. The heat dissipation device includes a base and one or more heat dissipation units. The base has a first side and an opposite second side; and the heat dissipation units respectively include at least one radiation fin correspondingly provided on the first side of the base. The radiation fin is formed by correspondingly closing a first plate member and a second plate member to each other, such that a plurality of independent flow channels is defined between the closed first and second plate member. The independent flow channels communicate with each other. And, the independent flow channels respectively have an amount of working fluid filled therein.

The present application is a continuation in part of U.S. patentapplication Ser. No. 16/251,077, filed on Jan. 18, 2019.

FIELD OF THE INVENTION

The present invention relates to a heat dissipation unit and a heatdissipation device using same, and more particularly, to a heatdissipation unit and a heat dissipation device using same, which havelargely increased heat dissipation efficiency.

BACKGROUND OF THE INVENTION

The currently available mobile devices, personal computers, servers,communication chasses, and many other electronic systems and apparatusesall provide highly upgraded computing power. However, the powerfulcomputing units inside these electronic systems and apparatuses alsoproduce increasing heat when they operate. Therefore, heat dissipationunits are necessary to help remove the produced heat. Among others, heatsinks, heat pipes, and vapor chambers are the heat dissipation elementsthat are most frequently chosen by users for removing heat from theirelectronic devices. In the case of large-area heat dissipation, heatdissipation devices together with cooling fans are usually used toenable forced heat dissipation.

Generally, a heat dissipation device includes a base and a plurality ofradiation fins located on one side of the base. In response to theincreasing heat produced by the electronic elements with highly upgradedcomputing power, the radiation fins on the base must have acorrespondingly increased size/height to provide more areas for morequickly dissipating the produced heat from the electronic devices.However, the heat dissipation efficiency of the radiation fins isreduced with the increased height thereof, which in turn results inlowered heat dissipation efficiency of the entire heat dissipationdevice.

In conclusion, the conventional heat dissipation device has thefollowing disadvantages: (1) having very low heat dissipationefficiency; and (2) having a relatively large volume.

It is therefore tried by the inventor to develop an improved heatdissipation unit and a heat dissipation device using same, in order toovercome the disadvantages of the conventional heat dissipation device.

SUMMARY OF THE INVENTION

A primary object of the present invention is to provide a heatdissipation unit that has largely increased heat dissipation efficiency.

Another object of the present invention is to provide a heat dissipationunit that enables a heat dissipation device using same to have a largelyreduced volume.

A further object of the present invention is to provide a heatdissipation device that has largely increased heat dissipationefficiency.

A still further object of the present invention is to provide a heatdissipation device that has a largely reduced volume.

To achieve the above and other objects, a preferred embodiment of theheat dissipation unit according to the present invention includes atleast one radiation fin, which is formed by correspondingly closing afirst plate member and a second plate member to each other, such that aplurality of independent flow channels is defined between the closedfirst and second plate members. The independent flow channelscommunicate with each other. And, the independent flow channelsrespectively have an amount of working fluid filled therein.

To achieve the above and other objects, a preferred embodiment of theheat dissipation device according to the present invention includes abase and a heat dissipation unit. The base has a first side and anopposite second side; and the heat dissipation unit includes at leastone radiation fin correspondingly provided on the first side of thebase. The radiation fin is formed by correspondingly closing a firstplate member and a second plate member to each other, such that aplurality of independent flow channels is defined between the closedfirst and second plate members. And, the independent flow channelsrespectively have an amount of working fluid filled therein.

According to the structural design of the present invention, by means ofthe independent flow channels disposed in the radiation fin incommunication with each other, when the second side of the base is incontact with a heat source, heat produced by the heat source is absorbedby the base and transferred from the second side to the first side ofthe base and then to the radiation fins. The heat transferred to theradiation fins is then absorbed by the working fluid in the independentflow channels in the radiation fins. When the working fluid is heatedand vaporized in the independent flow channels in communication witheach other, heat is quickly carried by the vapor-phase working fluid toanother ends of the independent flow channels that are farther away fromthe heat source. At the farther ends of the independent flow channels,the vapor-phase working fluid is condensed to a liquid. With the aid ofat least one wick structure provided on the inner wall surfaces of theindependent flow channels, the liquid-phase working fluid flows back tothe ends of the independent flow channels that are closer to the heatsource. In this way, the liquid-vapor circulation of the working fluidcontinues in the radiation fins to achieve the effect of quick heatdissipation to largely upgrade the heat dissipation efficiency of theheat dissipation device.

In another operable embodiment of the heat dissipation device accordingto the present invention, when the second side of the base is in contactwith a heat source, heat produced by the heat source is absorbed by thebase and transferred from the second side to the first side of the baseand then to the radiation fins. The heat transferred to the radiationfins is further transferred to a plurality of heat transfer elements,which are sandwiched between the first and second plate members of theradiation fins to define the independent flow channels in communicationwith each other therein. The heat transferred to the heat transferelements is then absorbed by the working fluid in the independent flowchannels in the heat transfer elements. Similarly, the liquid-vaporcirculation of the working fluid in the independent flow channelsupgrades the heat dissipation efficiency of the heat dissipation device.

Further, by providing the independent flow channels in communicationwith each other in the radiation fins or by providing the heat transferelements between the first and the second plate members of the radiationfins, it is able to overcome the problem of poor heat dissipationefficiency in the conventional heat dissipation device caused by theexcessively large volume of the radiation fins. In the presentinvention, the provision of the independent flow channels in theradiation fins to enable liquid-vapor circulation of the working fluidin each of the radiation fins allows the heat dissipation device of thepresent invention to have a largely reduced overall volume while havingeven better heat dissipation efficiency than the conventional heatdissipation device.

BRIEF DESCRIPTION OF THE DRAWINGS

The structure and the technical means adopted by the present inventionto achieve the above and other objects can be best understood byreferring to the following detailed description of the preferredembodiments and the accompanying drawings, wherein

FIG. 1 is an exploded perspective view of a first embodiment of the heatdissipation unit according to the present invention;

FIG. 2 is a sectional view of the heat dissipation unit of FIG. 1;

FIG. 3 is an exploded perspective view of a second embodiment of theheat dissipation unit according to the present invention;

FIG. 4 is an assembled perspective view of the heat dissipation unit ofFIG. 3;

FIG. 5 is a sectional view of the heat dissipation unit of FIG. 3;

FIG. 6 is an assembled perspective view of a third embodiment of theheat dissipation unit according to the present invention;

FIG. 7 is an assembled perspective view of a first and a secondembodiment of the heat dissipation unit according to the presentinvention;

FIG. 8 is a sectional view of a second embodiment of the heatdissipation device according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described with some preferredembodiments thereof and by referring to the accompanying drawings. Forthe purpose of easy to understand, elements that are the same in thepreferred embodiments are denoted by the same reference numerals.

Please refer to FIGS. 1 and 2, which are exploded perspective andsectional views, respectively, of a first embodiment of a heatdissipation unit 2 according to the present invention. As shown, theheat dissipation unit 2 in the first embodiment thereof includes atleast one radiation fin 20, which is formed by correspondingly closing afirst plate member 201 and a second plate member 202 to each other. Inthe first embodiment, the first plate member 201 is formed with one ormore recesses 210. However, it is understood the recesses 210 can beotherwise formed on the second plate member 202. More specifically, oneof the first and the second plate members 201, 202 of the radiation fin20 is formed with the recesses 210, while the other one of them is aflat member without any recess 210 formed thereon. The first and secondplate members 201, 202 are correspondingly mated with each other,whereby the recesses 210 of the first plate member 201 and the secondplate member 202 form multiple independent flow channels 21 incommunication with each other. As shown in FIG. 3, each of theindependent flow channels 21 is internally provided with a working fluid22 for heat transfer through liquid-vapor circulation of the workingfluid 22 in the independent flow channel 21. Further, each of theindependent flow channels 21 has at least one wick structure 23 or alayer of coating provided on inner wall surfaces thereof. The wickstructure 23 can be a mesh structure, a fibrous structure, a porousstructure or a grooved structure, and is mainly used to enhance theliquid-vapor circulation of the working fluid 22 in the independent flowchannels 21.

The coating can be provided on one or both of the inner wall surfaces ofthe independent flow channels 21 and the wick structure 23.

Please refer to FIGS. 3, 4 and 5, which is an assembled perspective anda sectional view of a second embodiment of the heat dissipation unitaccording to the present invention. Unlike the first embodiment, theheat dissipation unit in the second embodiment thereof includes at leastone radiation fin 20, of which the first plate member 201 and the secondplate member are formed with one or more first recesses 211 and one ormore second recesses 212, respectively. In other words, in the secondembodiment, both of the first and the second plate member 201, 202 ofthe radiation fin 20 have recesses formed thereon. Further, when thefirst and the second plate member 201, 202 are correspondingly closed toeach other, the first recesses 211 and the second recesses 212 arebrought to face and close one another in one-to-one correspondence tothereby form a plurality of independent flow channels 21 between theclosed first and second plate members 201, 202. As shown in FIG. 5, theindependent flow channels 21 in the second embodiment of the heatdissipation unit of the present invention are also internally providedwith a working fluid 22 and at least one wick structure 23.

To manufacture the radiation fin 20, first perform a mechanical processon one of the first and the second plate member 201, 202 to form therecesses 210; or perform the mechanical process on both of the first andthe second plate member 201, 202 to form the first and the secondrecesses 211, 212, respectively. The mechanical process includes a firststep of stamping one or both of the first and the second plate member201, 202 to form the recesses 210 or the first and the second recesses211, 212; and a second step of correspondingly closing and fixedlyholding the first and the second plate member 201, 202 to each other bywelding or any other suitable way, such that the recesses 210 formed onthe first plate member 201 or the second plate member 202 form theindependent flow channels 21, or the first and the second recesses 211,212 formed on the first plate member 201 and the second plate member 202form the independent flow channels 21. Thereafter, air is evacuated fromthe independent flow channels 21 and a working fluid 22 is filled intothe independent flow channels 21 via a fluid filling port 24 provided onthe radiation fin 20 (see FIG. 6). Finally, peripheral edges of therecesses 210 or of the paired and closed first and second recesses 211,212 as well as the fluid filling port 24 are sealed to complete theradiation fin 20. Herein, the working fluid 22 can be aqua ammonia, acoolant, water, hydrocarbon, or any other suitable compound.

It is noted the recesses 210 or the first and second recesses 211, 212are not limited to any specific shape, size, arrangement, or extendingdirection. For example, in a third embodiment of the heat dissipationunit 2, as shown in FIG. 7, the recesses 210 formed on the first or thesecond plate member 201, 202 are different in length and the longer andthe shorter recesses 210 are arranged alternately. In the firstembodiment of the heat dissipation unit 2 shown in FIG. 4, the recesses210 are parallelly formed on the first or the second plate member 201,202 to extend in a direction perpendicular to two opposite edges of thefirst or the second plate member 201, 202. Of course, the recesses 210can be otherwise parallelly formed on the first or the second platemember 201, 202 to extend at an angle with respect to two opposite edgesof the first or the second plate member 201, 202, similar to that shownin FIG. 7. That is, the shape, size, arrangement and extending directionof the recesses 210 or of the first and second recesses 211, 212 can beadjusted according to actual need in use, so long as when the first andsecond plate members 201, 202 are mated with each other, the recesses210 or the paired first and second recesses 211, 212 can form theindependent flow channels 21. In addition, the aforesaid coating (notshown) can be provided on inner wall surfaces of the independent flowchannels 21 and on the wick structure 23 or therebetween to enhance theliquid-vapor circulation of the working fluid 22 in the independent flowchannels 21

Please refer to FIGS. 6, which is an assembled perspective view of athird embodiment of the heat dissipation unit according to the presentinvention. The third embodiment is different from the first and thesecond one in that it further formed with multiple ribs 25. The ribs 25are not particularly limited in number, extending direction andarrangement, which can be freely adjusted according to actual need inuse. For example, the ribs 25 can be longitudinally or transverselyextended with respect to the radiation fin 20 or be arranged on theradiation fin 20 in a staggered manner. The purpose of the ribs 25 is togive the radiation fin 20 an increased structural strength, lest theradiation fin 25 should be easily deformed.

Please refer to FIG. 7, which is an assembled perspective view of afirst and a second embodiment of the heat dissipation unit according tothe present invention. As shown, in the first and second embodimentthereof, the heat dissipation device 4 includes one or more heatdissipation units 2 described above and a base 3. The base 3 has a firstside 30 and an opposite second side 31. On the first side 30 of the base3, one or more fixing grooves 300 are formed for respectively fixedlyholding one piece of the radiation fin 20 thereto. The radiation fins 20can be fixedly held to the fixing grooves 300 through interference-fit,riveting, welding, adhesive bonding, or snap-fit.

As can be seen in FIG. 8, when the second side 31 of the base 3 is incontact with a heat source 5, heat produced by the heat source 5 isabsorbed by the base 3 and transferred from the second side 31 to thefirst side 30 of the base 3 and then to the radiation fins 20. The heattransferred to the radiation fins 20 is then absorbed by the workingfluid 22 in the independent flow channels 21 in the radiation fins 20.When the working fluid 22 is heated and vaporized in the independentflow channels 21, heat is quickly carried by the vapor-phase workingfluid 22 to another ends of the independent flow channels 21 that arefarther away from the heat source 5. At the farther ends of theindependent flow channels 21, the vapor-phase working fluid 22 iscondensed to a liquid. With the aid of the wick structure 23 provided onthe inner wall surfaces of the independent flow channels 21, theliquid-phase working fluid 22 flows back to the ends of the independentflow channels 21 that are closer to the heat source 5. In this way, theliquid-vapor circulation of the working fluid 22 continues in theradiation fins 20 to achieve the effect of quick heat dissipation tolargely upgrade the heat dissipation efficiency of the heat dissipationdevice 4.

By providing the independent flow channels 21 in communication with eachother in the radiation fins 20, it is also able to overcome the problemof poor heat dissipation efficiency of the conventional heat dissipationdevice due to the large volume of the radiation fins thereof. In otherwords, in the present invention, the provision of the independent flowchannels 21 in the radiation fins 20 to enable liquid-vapor circulationof the working fluid 22 in each of the radiation fins 20 allows the heatdissipation device 4 of the present invention to have a largely reducedoverall volume while having even better heat dissipation efficiency thanthe conventional heat dissipation device.

In conclusion, compared to the conventional heat dissipation device, thepresent invention has the following advantages: (1) having largelyupgraded heat dissipation efficiency; and (2) having a largely reducedoverall volume.

The present invention has been described with some preferred embodimentsthereof and it is understood that many changes and modifications in thedescribed embodiments can be carried out without departing from thescope and the spirit of the invention that is intended to be limitedonly by the appended claims.

What is claimed is:
 1. A heat dissipation unit, comprising a base and aplurality of radiation fins attached to a first side of the base, eachof the radiation fins comprising: a first plate member; a second platemember closed to the first plate member, one or both of the first andsecond plate members having a plurality of recesses depressed on onesurface and protruding on an opposite surface of the one or both of thefirst and second plate members; a plurality of flow channels definedbetween the closed first and second plate members, the plurality of flowchannels connected together such that they are in fluid communicationwith one another; a wick structure provided in the plurality of flowchannels, the wick structure having the same three dimensional shape asthe plurality of flow channels; and working fluid filled in theplurality of flow channels, wherein outer faces of the first and secondplate members are configured to directly exchange heat with ambient airsuch that heat of a heat source attached to a second side of the base istransferred to the radiation fins, is absorbed by the working fluid inthe plurality of flow channels, and is carried by the working fluid in avapor phase to ends of the plurality of independent flow channels thatare distal the base.
 2. The heat dissipation unit of claim 1, whereinthe plurality of recesses include a plurality of first recesses formedon the first plate member and a plurality of second recesses formed onthe second plate member and wherein the correspondingly closed first andsecond plate members bring the first recesses and the second recesses toface and close one another in one-to-one correspondence, such that thepaired and closed first and second recesses form the plurality of flowchannels.
 3. The heat dissipation unit of claim 1, wherein the recessesare formed on the radiation fins by a mechanical process of stamping. 4.The heat dissipation unit of claim 1, wherein the wick structureprovided therein is selected from the group consisting of a meshstructure, a fibrous structure, and a porous structure.
 5. The heatdissipation unit of claim 4, wherein the radiation fins further includea coating provided on inner wall surfaces of the flow channels and/orthe wick structure.